Creevyx, Fear Unleashed

Eminence — As long as Creevyx, Fear Unleashed
is in the command zone or on the battlefield, you
may cast cards in exile with terror counters on
them. You may pay {b}{b}{b}{b}{b} instead of
paying the cost of spells cast this way.
When Creevyx enters the battlefield or attacks,
exile the top card of each player's library with a
terror counter on it.